Method of making sponge-rubber.



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J'OSEF HUEBNER, OF CHICAGO,

ILLINOIS.

METHOD OF MAKING SPONGE-RUBBER.

No Drawing.

To all whom it may concern.

4 lie it-kuown that l, J osnr HUEBNER, subject of the Emperor ofGermany, residmg at Chicago, in the county of Cook and State otIllinois, have invented certain new and useful Improvements in Methodsof Making Sponge-Rubber; and I do hereby declare the following to be afull, clear, and exact de-- scr-iption ot' the invention, such as willen'- able others skilled in the art to which it appertains to make anduse the same.

This invention has for its object to devise a novel process forproducing a superior quality of so-called sponge rubber, and consists inthe sereral steps and the mixture and treatnwnt of ingredientshereinafter fully described and particularly claimed.

in carrying out my process, I employ ordinary rubber vulcanizing moldsand the machinery ordinarily employed in the preparation of vuloanizablerubber compounds.

The particular object'of my invent on is to provide a sponge rubberwhich will be very tough and elastic and, which, furthermore, will notdry or become hard or br1ttle .except after the lapse of many years.

A number (it-the ingredients which I employ are commonly used to producesponge- -rubber but the product usually produced lacks the resiliencyand toughness desired where it is used as a cushion, and, furthermorethis product rapidly deteriorates. and becomes hard and brittle.

Theessence of theinvention resides in the 535 addition to a vulcanizablerubber compound of a liquid preservative which is substantiallynon-drying and does not chemically adect the rubber deleteriou'sly butmaintains the same at all times moist and, by reason of its preservativequalities, greatly increases the life thereof, and insubjecting theresulting mixture Within a mold during consecutive intervals of time tosuccessively increased temperatures, whereby the volatile ingredients inthe mixture will be uniformly "olatilized throughout the mass before thelatter is vulcanized.

Other advantages gamed reside n the mcreased toughness and elastic1ty=of the product whereby it will respond 1 instantly likespring to therelease of pressure applied.

thereto.

--Tl1e compound'is preferably made and de i scribed in the followingmanner and when so made is, so far as my experiments have demonstrated,possessed of the most desir- Specification of Letters Patent.

Patented July 14, .1914.

Application filed January. 25, 1913. Serial No. 744,171.

able qualities and advantages,but the proportions of ingredients usedand the time and temperatures of vulcanization may be variedwithmltfdeparting from the irrvent1on. The ingredients named have beenfound best adapted but equivalents thereof may be substituted withoutdeparture-from the invention.

In producing the said compound I employ by weight substantially thefollowing proportions of ingredients; vizz. sixty (60) parts rubber gum,live parts resin oil, ten (10) parts zine oxid, ten (10) parts spiritsof turpentine, five parts flour of sulfur, :ten (10) parts ammoniumcarbonate.

In mixing these ingredients I first add to the rubber gum, which hasbeen thereto'fore worked through the usual rolls to primarily produce adough, the said resin oil and after this has been added the said gum ordough is again passed through the rolls repeatedly until the resin oilhas been thoroughly :distributed through the mass in a finely dividedstate. I then add the zinc oxid which is also Working the gum againthrough the rolls repeatedly and this operation [is successivelyrepeated after adding turpentine, flour sulfur and ammonium carbonate inthe order named. The resulting compound is then placed in a mold in theusual manner and is subjected to heat by means of steam surrounding themold in the usual manner exsimilarly distributed through the mass by r(5) pounds at a time and maintained substantially the same number ofminutes as the pounds pressure indicated until thirtylive (35) poundspressure more or less has been attained in the vulcanizer; this beingthen continuously maintained for one (1) hour and fifty '(50) minutes,but, in' the event thatthe mass tojbe vulcanized is excessively large,the last named-pressure may bemaintained for proportionately longerperiod, and thereafter'the'mol'd is permitted to cool preferablygradually but such cooling maybe aeeelerated without injury to thevulcanized product.

During. the initial steps of heating which precede the vulcanization thevolatile constituents consisting of the turpentine and ammoniumcarbonate are transformed into gas globules which expand and producecells, the prolonged continuation of the heat at a point below thatrequired for the vul-- .can-ization giving the finely divided volatilematter time -to become fully expanded before the rubber compound becomesset.

At each increase of temperature the heat, being applied through the moldhousing the compound or mixture, first expands the outer cells or poresand if the temperature were continuously increased up to the point ofvulcanization, the outer or surface cells would be considerably largerthan those in the interior of the vulcanized mass. avoid this, Imaintain the temperature applied to the mold substantially constantafter each rise in temperature for a sufficient 'drying substance, and,when admixed with the compoundto impregnate the latter therewith,prevents such com ound from becoming hard and brittle an otherwisedeterio-' rating as is usual with compounds of this nature. The saidresin, oil also acts as a preservative, thereby insuring a product of rpermanent elasticity.

.The foregoing proportions of the several ingredients maybe slightlychanged and varied without departing from the invention as may also thetimeand temperatures employed in vulcanization, that is to say,"a

, variation from the proportions and time and temperatures given of ten(10) to fifteen (15) per-cent. would produce results very similar tothose produced by using the exact proportions, temperatures and timeabove given. The resulting compound is particularly adapted as a fillingfor tires or other d ,vices such as rubber-stamps and the like, in whichresiliency is required' The compound is exceedingly elastic and quick toreact after compression and is, therefore,

particularly adapted to all purposes where liveliness is a requis te. 1

I claim as my inaentionf 1. The process for producing sponge rubberwhich consists in'intimately admixing with a vulcanizable rubbercompound a plurality of volatile ingredients adapted to be transformedinto for vulcanization of said compound; placing said compound in a.mold and subjectingit successively to increasing degrees of heat eachadapted to transform at least one of said volatile ingredients andmaintaining each succeeding degree of heat for a period requisite topenetrate the whole mass, and

finally increasing said temperature to the point and for the periodrequisite to-vulcanize said compounv 2. The process for producing spongerubgaseous fluids at varioustemperatures none greater than that.required ber of substantially uniform'porosity and permanent elasticitywhich consists'in mixing a vulcanizable rubber compound with anon-drying liquid adapted to preserve the compound after vulcanizationthereof, and

with a plurality of ingredients adapted upon heating to be vaporized atdifferent temperatures to form cells in the compound; placing theresulting mixture in a mold and subjecting the mold for appreciableintervals of: time, respectively, to a series ofteniporarily-maintained\ successively higher temperatures correspondingto those required for vaporizing the said ingredients respectively; andthereafter sub ecting the said mold to a temperature suflicient thecontents thereof. 1 i v 3. The hereindescribed process-for 'pro- 'ducingsponge rubber which consists in admixing with rubber successively 'atdifiercnt intervals, resin oil, zinc oxid, turpentine,

flour of sulfur and ammoniumcarbonate in 'the proportions, more orless,:named, and thereupon vulcanizin'g the mass byplacing the same inamold, placing the latter in a' vulcanizer and admitting steam tothelatter atintervals at successively higher temperature to graduallyincrease the temperature of the compound until a maximum ofsubstantially thirty-five pounds pressure is attainedand maintaining;the said pressure fora period of one'and five-sixths hours more or less.a i

In testimony whereof I have signed my name in presence of twosubscribing witnesses. c JosEF HU B' ER;

Witnesses: I a

' M. BOYLE,

ALBERT SomnBLn.

to vulcanize

